The National Institute for Health and Clinical Excellence (NICE) is the independent organisation responsible for providing national guidance on the promotion of good health and the prevention and treatment of ill health. NICE also produces quality standards that set out what high-quality care in the NHS should look like, and support tools for providers and commissioners in the NHS and local authorities. From 2013, NICE will produce quality standards for social care, as part of its expanding remit. This manual describes the methods used by the Centre for Public Health Excellence (CPHE) in NICE to develop and update public health guidance. It is aimed at: External agencies undertaking evidence reviews and economic modelling for CPHE. Other contractors engaged in the guidance production process (for example, those conducting fieldwork). Members of NICE's public health advisory committees (PHACs) that develop public health guidance. Staff in CPHE and other NICE teams that contribute to the development and dissemination of public health guidance and related products. This third edition has been prepared by CPHE staff, drawing on experience of the first 7 years of public health guidance development at NICE. It is based on international criteria of quality for guidance development, as outlined by the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument. The structure of this manual follows the methods for development of NICE public health guidance from inception to publication. An overview of the processes for public health guidance development is described in The NICE public health guidance development process (third edition, 2012). The manuals define the philosophical and methodological principles that govern the production of guidance. They also set out the operational framework that contractors, advisory committees and the CPHE team will follow. The manuals are prescriptive to ensure the: Aims and objectives of guidance production are as clear as possible. Procedures used are as systematic, transparent, auditable and accountable as possible.